115 Classification, Clinical Manifestations, and Evaluation of Disorders of Hemostasis

Question 1

The most frequent acquired disorder in hemostasis

Answer 1

Thrombocytopenia

Question 2

TRUE OR FALSE

If hypersplenism is the sole cause of a hemostatic disorder, it is rarely severe enough to cause pathologic bleeding.

Answer 2

TRUE

If hypersplenism is the sole cause of a hemostatic disorder, it is rarely severe enough to cause pathologic bleeding.

Question 3

Typical patterns of bleeding

Unprovoked hemarthroses and muscle hemorrhages:

Answer 3

Unprovoked hemarthroses and muscle hemorrhages: hemophilias

Question 4

Typical patterns of bleeding

Mucocutaneous bleeding- epistaxis, gingival bleeding, menorrhagia:

Answer 4

Mucocutaneous bleeding- epistaxis, gingival bleeding, menorrhagia: qualitative platelet disorders, thrombocytopenia, or von Willebrand disease

Question 5

Obtaining objective confirmation of the subjective information conveyed in the bleeding history is valuable. Objective data include:

Answer 5

1. Previous hospital or physician visits for bleeding symptoms
2. Results of previous laboratory evaluations
3. Previous transfusions of blood products for bleeding episodes
4. A history of anemia and/or previous treatment with iron

Question 6

The most commonly used herbals that can cause platelet dysfunction and induce bleeding.

Answer 6

Ginkgo biloba and ginseng

Question 7

A nutrition history should be obtained to assess the likelihood of:

Answer 7

• Vitamin K deficiency, especially if the patient also is taking broad-spectrum antibiotics
• Vitamin C deficiency, especially if the patient has skin bleeding consistent with scurvy (perifollicular purpura); and
• General malnutrition and/or malabsorption.

Question 8

Tissues that have an increased local fibrinolytic activity:

Answer 8

• Urinary tract
• Endometrium
• Mucous membranes of the nose and oral cavity

These sites are particularly likely to have prolonged oozing of blood after trauma in patients with hemostatic abnormalities

Question 9

Bleeding resulting from defects in fibrin crosslinking (factor XIII deficiency), or fibrinolytic defects may often manifest as:

Answer 9

Delayed bleeding after trauma

Question 10

TRUE OR FALSE

Bleeding isolated to a single organ or system (eg, hematuria, hematemesis, melena, hemoptysis, or recurrent nosebleeds) is less likely to result from a hemostatic abnormality than from a local cause

Answer 10

TRUE

Bleeding isolated to a single organ or system (eg, hematuria, hematemesis, melena, hemoptysis, or recurrent nosebleeds) is less likely to result from a hemostatic abnormality than from a local cause

Question 11

Example of blood vessel disorders that may cause bleeding

Answer 11

Hereditary hemorrhagic telangiectasias, Cushing disease, scurvy, or Ehlers-Danlos syndrom

Many primary dermatologic disorders also have a purpuric or hemorrhagic component and must also be considered in the differential diagnosis

Question 12

Mode of inheritance of hemophilia A or B:

Answer 12

Sex-linked pattern

Question 13

Mode of inheritance of most forms of von Willebrand disease:

Answer 13

Autosomal dominant

Question 14

Mode of inheritance of pattern typical for all other coagulation factor deficiencies, inherited platelet disorders, and the rare, severe (homozygous), type 3 von Willebrand disease

Answer 14

Autosomal recessive

Question 15

Population genetic information may be helpful; for example, the higher prevalence of ________ deficiency in Ashkenazi Jews.

Answer 15

Factor XI deficiency

Question 16

One of the most common signs of platelet disorders and von Willebrand disease.

It also is the most common symptom of hereditary hemorrhagic telangiectasia.

Answer 16

Epistaxis

Epistaxis is not uncommon in normal children, but it usually resolves before puberty.

Dry-air heating systems can provoke epistaxis even in otherwise normal individuals.

Question 17

TRUE OR FALSE

Bleeding confined to a single nostril more likely results from a local vascular problem than a systemic coagulopathy.

Answer 17

TRUE

Bleeding confined to a single nostril more likely results from a local vascular problem than a systemic coagulopathy.

Question 18

TRUE OR FALSE

Excessive bruising is more common in men than women.

Answer 18

FALSE

Excessive bruising is more common in women than men.

Moreover, women frequently note that the severity of their bruising varies with the phase of their menstrual cycle, although the most severe phase of the cycle may differ per woman.

Question 19

Red bruises on the extensor surfaces of the arms and hands indicate loss of supporting tissues, as occurs in :

Answer 19

Cushing syndrome, glucocorticoid therapy, senile purpura, and damage from chronic sun exposure

Question 20

Jet-black bruises may be caused by :

Answer 20

Warfarin-induced skin necrosis and similar disorders

Question 21

A hereditary disorder characterized by local angiodysplasia, mostly present in the skin, mucous membranes, and often in organs such as the lungs, liver, and brain .

It may lead to nose bleeding or acute and chronic digestive tract bleeding

Also manifest with easy bruising

Answer 21

Rendu-Osler-Weber disease

Question 22

Manifested by distensible skin or extraordinary ligament laxness and in patients with hyperflexibility of the thumb

Also manifest with easy bruising

Answer 22

Ehlers-Danlos syndrome

Question 23

TRUE OR FALSE

Molar extractions are greater hemostatic challenges than extractions of other teeth.

Answer 23

TRUE

Molar extractions are greater hemostatic challenges than extractions of other teeth.

Question 24

TRUE OR FALSE

Hemoptysis almost often is the presenting symptom of a bleeding disorder and is common even in patients with serious bleeding disorders.

Answer 24

FALSE

Hemoptysis almost never is the presenting symptom of a bleeding disorder and is rare even in patients with serious bleeding disorders.

Melena, hematemesis, like hemoptysis, almost never is the presenting symptom of a hemostatic disorder

Question 25

TRUE OR FALSE

Hematuria is rarely the presenting symptom of a hemostatic disorder except for the hemophilias

Answer 25

TRUE

Hematuria is rarely the presenting symptom of a hemostatic disorder except for the hemophilias

Question 26

Rectal bleeding in individuals with normal hemostasis most often results from:

Answer 26

Hemorrhoids

Question 27

Menorrhagia is common in women with platelet disorders and von Willebrand disease.

In general, menstrual bleeding is considered excessive if the patient indicates she has heavy flow for more than _______ days or total flow for more than _________days.

Answer 27

More than three days or total flow for more than seven days

However, an objective distinction between menorrhagia (loss of >80 mL of blood per period) and normal blood loss can only be made by a visual assessment technique using pictorial charts of towels or tampons.

Question 28

Childbirth poses a considerable hemostatic challenge. Consequently, patients with bleeding disorders commonly manifest excessive bleeding during or after labor, necessitating blood transfusion.

An exception is:

Answer 28

Mild and moderate von Willebrand disease

There is vast increase in von Willebrand factor during pregnancy.

Question 29

Habitual spontaneous abortions raise the possibility that the patient has a:

Answer 29

Quantitative or qualitative abnormality of fibrinogen, factor XIII deficiency, or the antiphospholipid syndrome

Question 30

Are the hallmark abnormality in the hemophiliac; they are rare in other disorders except in severe factor VII deficiency and type 3 von Willebrand disease

Answer 30

Hemarthroses

Question 31

Characteristic of factor XIII deficiency and afibrinogenemia

Answer 31

Bleeding from the umbilical stump

Question 32

Range from pinpoint erythematous dots that blanch with pressure to classic cherry angiomata ranging in size up to several centimeters

Answer 32

Telangiectasias

Question 33

More florid lesions that characteristically affect the vermilion border of the lips and the tongue (including the underside of the tongue)

Answer 33

Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease)

Question 34

Found in patients with chronic liver disease have a more splotchy and serpiginous appearance

Concentrated on the shoulders, chest, and face

Answer 34

Spider telangiectasias

Question 35

A prolonged aPTT as a sole abnormality can be caused by:

Answer 35

• Deficiency of factor VIII, IX, XI, or XII;
• Presence of heparin;
• Presence of an inhibitor, which can be either factor specific, such as an antibody against factor VIII, or factor nonspecific, such as the presence of heparin or a lupus anticoagulant

Question 36

A prolonged PT as the sole finding can indicate

Answer 36

• Factor VII deficiency
• Mild vitamin K deficiency
• Presence of an inhibitor

Question 37

Abnormalities of both PT and aPTT may indicate

Answer 37

• Deficiency of fibrinogen, prothrombin, factor V or factor X
• An inhibitor to one of these factors
• A combined deficiency of coagulation factors

Question 38

Used to distinguish between a deficiency state and the presence of an inhibitor

Answer 38

Mixing studies

Repeating the abnormal test, the PT and/or aPTT, using a 1:1 mixture of the patient’s plasma and normal plasma

If the mixture normalizes the prolonged PT or aPTT, a deficiency state is likely

If the mixture still yields a significantly prolonged PT or aPTT, an inhibitor probably is present.

Question 39

TRUE OR FALSE

Some inhibitors, such as antibodies to factor VIII, require time to inhibit the factor VIII activity in the assay, whereas other inhibitors, such as lupus anticoagulant or heparin, do not.

Consequently, incubating the mixture for four hours at 32C before performing the coagulation assay is desirable.

Answer 39

FALSE

Some inhibitors, such as antibodies to factor VIII, require time to inhibit the factor VIII activity in the assay, whereas other inhibitors, such as lupus anticoagulant or heparin, do not.

Consequently, incubating the mixture for one or two hours at 37 C before performing the coagulation assay is desirable.

Question 40

Tests done if none of the initial test results (PT, aPTT, and platelet count) is abnormal and the patient exhibits bleeding manifestations

Answer 40

Ristocetin cofactor (RCF) or von Willebrand factor activity and examination of the blood film

Question 41

TRUE OR FALSE

The bleeding time is not used anymore because the test is highly operator and situation (eg, room temperature, skin circulation) dependent and is not sufficiently reliable to be useful in the diagnostic process.

Answer 41

TRUE

The bleeding time is not used anymore because the test is highly operator and situation (eg, room temperature, skin circulation) dependent and is not sufficiently reliable to be useful in the diagnostic process.

Instead, many laboratories have introduced the platelet function analyzer to detect qualitative defects in primary hemostasis.

Question 42

Characterized by presence of giant platelets on blood film

Answer 42

Bernard-Soulier syndrome

Question 43

Useful for distinguishing type 2B and platelet-type von Willebrand disease from the other types of von Willebrand disease

Answer 43

Ristocetin-induced platelet aggregation test

In type 2B and platelet-type von Willebrand disease, an enhanced response to low concentrations of ristocetin is observed, whereas in the other types of von Willebrand disease, a decreased response is found.

Question 44

Characteristics of total absence of platelet aggregates in a blood film prepared from nonanticoagulated blood and absent clot retraction

Answer 44

Glanzmann thrombasthenia

Question 45

Thrombin time (time for plasma to clot after adding thrombin) is prolonged in:

Answer 45

(a) afibrinogenemia, hypofibrinogenemia, and dysfibrinogenemia
(b) the presence of heparin
(c) disseminated intravascular coagulation (DIC) causing increased levels of fibrin(ogen) degradation products, which inhibit fibrin monomer polymerization
(d) patients with amyloidosis and an immunoglobulin inhibitor of thrombin

Question 46

The preoperative risk assessment of hemostasis is based on:

Answer 46

• Bleeding history
• Physical examination
• The underlying disorder if any,
• The type and site of surgery that is planned
• The results of basic hemostatic tests (PT, aPTT, platelet count)
• In addition to the extent of the surgical trauma, the magnitude of the fibrinolytic activity at the surgical site must be considered.
• The ability to institute local hemostatic measures should be considered.

Question 47

Surgeries expected to induce hemostatic defects

Answer 47

Open heart surgery or brain surgery

Question 48

Surgeries with sites of local fibrinolysis

Answer 48

Prostatectomy, tonsillectomy, oral or nasal surgery

Question 49

Surgeries where local hemostatic control is ineffective

Answer 49

Liver, lung, or kidney biopsy

Question 50

PBS: giant platelets and Dohle bodies in leukocytes

Answer 50

May-Hegglin and other MYH9 platelet syndromes

Question 51

PBS: moderately enlarged platelets

Answer 51

Immune thrombocytopenia or other conditions associated with shortened platelet survival

Question 52

PBS: small platelets

Answer 52

Wiskott-Aldrich syndrome

Question 53

PBS: schistocytes and burr cells

Answer 53

Hemolytic uremic syndrome and thrombotic thrombocytopenic purpura and occasionally in DIC

Question 54

The activities of factors II, V, VII, and X usually are determined in _________ assays, whereas the activities of factors VIII, IX, XI, and XII, prekallikrein, and high-molecular-weight kininogen are measured in ________ assays.

Answer 54

Factors II, V, VII, and X : PT-based assays

factors VIII, IX, XI, and XII, prekallikrein, and high-molecular-weight kininogen: aPTT-based assays

Question 55

The plasma level of fibrinogen most commonly is measured by

Answer 55

Assessing the time required for thrombin to clot the patient’s diluted plasma (Clauss method)

Question 56

Used in measuring factor XIII activity

Answer 56

Assays of transglutaminase activity

Simple qualitative test based on dissolving a fibrin clot in 5 M urea

Question 57

Measures the ability of the patient’s plasma to support the agglutination of a suspension of formaldehyde-fixed normal platelets by ristocetin

Answer 57

RCF activity

Question 58

Most common cause of prolonged aPTT on mixing studies

Answer 58

Presence of heparin in the sample

This cause can be verified by finding a prolonged thrombin time on a test of the patient’s plasma that is corrected with toluidine blue or other agents that neutralize heparin.

Question 59

TRUE OR FALSE

With lupus anticoagulant, the PT usually is less prolonged than is the aPTT, and aPTT reagents have markedly different sensitivity to lupus-type anticoagulant depending on the amount of phosphatidyl serine present in each reagent.

Answer 59

TRUE

With lupus anticoagulant, the PT usually is less prolonged than is the aPTT, and aPTT reagents have markedly different sensitivity to lupus-type anticoagulant depending on the amount of phosphatidyl serine present in each reagent.

Question 60

Originally was designed to quantify factor VIII inhibitors but can be modified to detect other inhibitors of coagulation factors

Answer 60

Bethesda assay

Question 61

Used to detect qualitative defects in primary hemostasis

Answer 61

Platelet function analyzer